Electrically assisted power steering systems can provide advantages over mechanically driven hydraulic steering systems. For example, the amount of steering assistance provided to a driver of a vehicle can be varied between drivers. In other words, one driver may be provided more assistance than another driver of the same vehicle. Further, the steering assistance can be varied according to a wide array of driving conditions. In one illustration, one level of electrical steering assistance may be provided to a driver when the vehicle is traveling in a forward direction and a second level of electrical steering assistance may be provided when the vehicle is traveling in a reverse direction. Similarly, one level of electrical steering assistance may be provided at lower vehicle speeds while a second level of electrical steering assistance is provided at higher vehicle speeds. However, after a vehicle is stopped it may require time to power up the electrical power steering system. Consequently, steering the vehicle may be difficult immediately after an engine start.
The inventor herein has recognized the above-mentioned disadvantages and has developed a method for improving electrically assisted vehicle steering. One example of the present description provides for a vehicle launch control method, comprising: adjusting a load of an alternator applied to an engine in response to a steering input and an engine torque request.
Thus, vehicle launch may be improved by considering vehicle steering input and engine torque request. In particular, when a steering angle input or a steering torque is at a higher level, power supplied by the engine to an electric steering system can be increased so that the vehicle can start to turn more quickly. On the other hand, if an engine torque request is at a higher level, additional engine torque may be provided to vehicle wheels to improve vehicle acceleration. Further, when the engine torque demand and the steering angle are at medium levels, engine power may be supplied to vehicle wheels and the electric steering system in response to weighted engine torque request and steering input.
The present description may provide several advantages. Specifically, the approach may improve vehicle launch so that a driver experiences smoother engine torque during vehicle acceleration. In addition, the approach may improve alternator field control during automatic engine starts. Further, the approach may provide improved engine torque arbitration and engine speed control for vehicles with electric steering systems.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.